Abstract
Changes in the permeability of the blood-CNS barrier are known to occur in a number of pathologic conditions involving the central nervous system. 1 Of the many tests devised for measuring such changes in permeability, that of Mestrezat and Gaujoux, 2 based on the passage of nitrate ions through the barrier into the spinal fluid, is one of the simplest. This test, which is roughly quantitative, proved in our hands to be so crude that the results in any single instance were difficult to interpret; however, by employing a large series of monkeys we 3 have been able to demonstrate that an increased barrier permeability to sodium nitrate occurs in experimental poliomyelitis.
Because the crudeness and unreliability of the nitrate test far outweighed any advantages accruing from the simplicity of the analytical procedure, we 4 later replaced this method with the Walter bromide test, 5 adapted by us to meet the needs of experimental work on monkeys. This test was found to be much more accurate than the nitrate method; in fact, it was usually possible for the analyst, who had no previous knowledge of the clinical status of the animals tested, to report whether or not the animals were infected, something which could only occasionally be done with the nitrate test. For this reason we thought it desirable to compare the two tests, barrier permeability being tested on the same animal by both methods simultaneously.
The comparative tests were done on 54 rhesus monkeys (Macaca mulatta), 33 of which were in the acute stages of poliomyelitis. The control series consisted of 10 normal, healthy monkeys and 11 animals which had been injected intracerebrally with 1.0 cc of normal monkey spinal fluid, 1.0% normal monkey cord suspension or 2.0% starch to determine the effect of trauma on the permeability of the barrier.
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